<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./demo11.js"></script>
    <style>
        #div_parent{
            width: 600px;
            height: 500px;
            background-color: blueviolet;
        }
        #div_child{
            width: 300px;
            height: 250px;
            background-color: aqua;
        }
    </style>
</head>
<body>
    <form>
        <input type="text" id="username" name="username" value="" placeholder="请输入用户名"> </br>
        <input id="password" name="password" placeholder="请输入密码">
    </form>
    <div id="div_parent">
        父div
        <div id="div_child">子div</div>
    </div>
    <div>
        <ul>
            <li>苹果</li>
            <li>葡萄</li>
            <li>香蕉</li>
        </ul>
        <a href="https://www.baidu.com/">百度</a>
    </div>
</body>
</html>